I've been a Sennheiser fan for a long time. My current set that I'm comparing these against is an HD 518 (through a seperate headphone amp). I usually advocate that those who care about sound quality get a good set of stero headphones like the 518s and use a standalone USB mic. I was excited when I heard Sennheiser was getting into the gaming industry a few years ago, but had no real need to replace my current setup.

Build Quality

Solid. They feel heavy duty, nothing creaky. I'm a little worried about the mic mute switch design, but it's held up so far and doesn't show any signs of wear. I think for the price, the cord should have been of a higher quality (maybe a braided jacket or something). The ear cups, on the other hand, feel premium and are replaceable according the manual though I wasn't given any alternates to test. I should note that I have a huge head and these fit comfortably without feeling like they're gonna snap, so that's a plus! Feels great after a long gaming session, no headache or pinched feeling. The volume knob is solid, if a little too tight to turn. Like most volume controls I deal with it feels like below 10% is off, 10-80% is the same volume and then you only get one level of loud at the top end.

Surround

This is why we're here, right? In stereo content, the surround effect is ok. It gives a bit more of a spatial effect, but it won't trick you into thinking it's the real thing.

But this is a gaming headset, so how does it work in a game? Pretty damn good, it turns out. I loaded up Final Fantasy XIV to give this headset a spin, mostly because it was raid night and I had a chance to get my squad's opinions on Discord (people who are used to hearing my voice) and I wasn't really expecting much from the game, but I play it a lot so I should notice a difference pretty easily. The final floor of the current raid tier has a giant eyeball to the side of the arena that you need to keep track of, as it jumps from place to place I was surprised to find I could locate it by sound before I spun the camera around to find it. After a few wipes (we haven't cleared it yet), I started to trust the sound effect and didn't even bother looking for the eye... "Oh it's on the right this time" I'd think as the effect played. It never let me down.

I also demoed some speaker test youtube videos like this one:The spatial effect worked well there. Watched a couple of movie clips and the 7.1 works like a charm. Bullets whizzing by your head, choppers coming in from behind and above, just like at the theater.

Stereo

I listened to some music, and while I don't feel these are as good for that as my open-backed 518s in a quiet room, the closed nature of these will help if you are in a noisier environment. They are NOT noise cancelling however, so for very noisy environments they won't help much. That said, the sound is full, and pleasantly neutral, though I did get some distortion in the low-end with some bass heavy music (rap).

Microphone

My raid squad said I sounded great, better than before. Though some of that might be due to the closeness of the boom mic to my mouth vs the desktop microphone a few feet away. You can mute the mic by putting the boom up, which works as advertised. There's a mechanical "click" as it engages/disengages to let you know. The mic is "monitored", you can hear yourself talk, there's no delay so it's not weird, but I don't usually run that way, and I couldn't figure out how to turn it off (the usual windows way of unchecking "listen to this device" yielded no results).

Value

$249 is a little out there for a gaming headset IMHO. I really feel like for that money, they should have been a 3.5mm plug into a USB DAC so these could be used outside of the PC environment (even if it was in stereo mode only). And as mentioned above, it could've used a more premium cord.

Overall

I enjoy this headset enough that it will probably be my daily driver for a while, at least for games where a mic is needed for voice comms. It might be worth it to keep an eye out for a sale though, as they do feel a bit pricey.